Fig. 3. rho expression in C1 is regulated by abdA and is sufficient to induce thoracic oenocytes. (A-C) Rho is initiated in all C1 homologues at stage 10 (A) but is maintained at early (B) and late (C) stage 11 only in abdominal C1. (D) Ato is expressed in both thoracic and abdominal C1 at stage 10. (E) Rho fails to be maintained in abdA^M1 mutants. (F) Rho is prolonged in the thorax by driving AbdA with ato-GAL4. (G-I) rho-lacZ recapitulates Rho maintenance in abdominal C1 (G) and is ectopically expressed in stage 11 thorax by driving AbdA (H) but not Ubx (I) with ato-GAL4. (J,K) ato-GAL4 driving Rho in either a wild type (J) or Scr⁴ Antp²⁵ (K) background produces oenocytes in T1-T3. (L) The timing of induction is not altered by prematurely providing sSpi using en-GAL4. (M) Numbers of thoracic oenocytes produced by misexpressing Rho or sSpi with the drivers indicated.